Device for working weak-current installations.



F. SCHBUTER.

DEVICE FOR WORKING WEAK CURRENT INSTALLATIONS. APPLICATION men m. 20. 1914.

1,141,836. Patented June 1, 1915.

5 SHEETS-SHEET I.

Fig.1.

Ill-rill F. scHnb'TEn.

DEVICE FOR WORKING WEAK CURRENT INSTALLATIONS. APPLICATION mm m. 20, m4.

1,141,836. Patented June 1, 1915.

5 SHEETS-SHEETZ.

F. scnn'o'm.

DEVICE FOR WORKING WEAK CURRENT INSTALLATIONS nrmcmou mm "3.20. 1914.

1,141,836. Patented June 1, 1915.

5 SHEETSSHEET 3.

Fig.5.

Earth F. SCHRUTER. DEVICE FOR WORKING WEAK CURRENT INSTALLATIONS. APPLICATION FILED FEB. 20, I914.

1,141,836. Patent/ed June 1, 1915.

5 SHEETS-SHEET 4.

F. scHnb'TEn.

DEVICE FOR WORKING WEAK CURRENT INSTALLATIONS.

APPLICATION FILED FEB, 20. 1914.

1,141,836. Patented June 1, 1915.

5 SHEETS-SHEET 5.

UNITED STATES PATENT OFFICE.

FRITZ SCI-IBbTER, OF WILMEBS DORF, NEAR BERLIN, GERMANY, ASSIGNOB, TO THE FIRM OF ELEKTRIZITATS-AKTIENGESELLSCHAFT HYDRAWERK, F CHARLOTTEN- IBURG, NEAB BERLIN, GERMANY.

DEVICE FOR WORKING WEAK-CURRENT INSTALLATIONS.

Specification of Letters Patent.

Patented June 1, 1915.

Application filed February 20, 1914. Serial No. 819,981.

[b all whom it may concern:

Be it known that I, FRrrz Sonuiirnn, a :itizen of the German Empire, and resident )f Wilmersdorf, near Berlin, Germany, have nvented certain new and useful Improvenents in and Relating to Devices for Work-- ng Weak-Current Installations, of which be following is a specification.

The object of the present invention is a )rocess to ether with a device shown in several modifications for working weak current nstallations, e. 9'. bell installations, by means of storage cells or batteries, the con- :umption of the energy stored in the ac- :umulators being automatically restored ?rom time to time to a. certain extent by :onnection with power or charging current ines, so that the storage cells can never be ither over discharged on over charged. The-connection of the accumulators to the |ower line is made through contacts operted by a relay placed in the weak current ircuit, or in an auxiliary current circuit arallel thereto. This relay can, however, nly be operated by proper connections after he dischar e of a certain quantity of amere-hours rom the accumulators; as lon however, as the accumulators are still su iently charged the relay is automatically at out or short-circuited.

In the accompanying drawings, Figure 1 epresents an installation of a bell circuit ith means to charge the accumulator as the ell is operated; Fig. 2 shows a modificaion in which both sides of the charging urrent circuit are broken; Fig. 3 is a fur- 181' modification showing resistances in 0th sides of the chargin current circ'uit; ig. 4 is. a further mo fication showing leans to connect and disconnect a condenser t the same time the charging current is conected and disconnected; Fig. 5 shows a Lodification of Fig. 1 in which means are sed to limit the charging periods; Fig. lOWS an arrangement uti izing changes in le specific gravity of the electrolyte to close 1e charging circuit; Figs. 7 and 8 show LOdlfiCfilLlOIlS in which a separate storage ittery receives the charge, and in its turn Larges the operating battery; Fig. 7 is a odificati'on in part, of Fig. 7; and Fig. 9. LOWS a modification in which an alternatg current may be used as the charging lrrent. p

In Fig. 1 is shown diagrammatically a set of connections wherein for the sake of simpliclty the above mentioned charging or discharg ng limiter is at first omitted. The charging current line (continuous current, light or power line) is marked 1, 2; the conductor 2 is earthed. At 3, 4 a double line branches ofl' to the side. The positive sectlon receives a fuse 5, a series resistance 6 for reducing the tension, and then goes to the contact device 7, 8 which in a normal state is open and which can be closed by turning the relay lever 9. The condenser 10 is connected in parallel with 7 8, in order to prevent excessive formation of sparks. The conducting part of the relay lever is connected with the positive pole of the operating storage battery 12 by way of 9 and the branching point 11; the return line to the heavy current network is by way of 13, 14. This branch has by connection to the earthed conductor 2 no pressure in relation to earth. The return line 1 1 to the charging current net-work is superfluous if an other earth connection is possible in the vicinity of the device. From the branching point 11 the positive section 15 leads to the bell installation 16; naturally there may be any number of them connected in parallel to each other. The same applies to other kinds of weak current circuits; the bell installa tion will, however, be taken here all the way.

through as an example. The return line of the bell installation is marked 17. It does not conduct back direct to the negative pole of the battery, but through relay electro-magnet 18 and thence by way of 13.

If the weak current circuit is closed by pressing any one circuit-closing contacts or push buttons 16 of the bell installation the a current flows from the positive pole oi the battery by way of 11, 15 through the bell installation 16 by way of the bell and the push button, then back by way of 17 through the relay electromagnet 18, and finally by way of 13 to the negative pole of the battery. The relay is so adjusted that it functions throughout the duration of the closing of the circuit in the weak current circuit, although the bell as is well known produces an in termittent current. In other words it must possess a certain activity. The electromagnet 18 thus attracts its armature 19, so long as theweak current circuit is kept closed. Thereby, however, the contact 7, 8 is closed by tipping the relay lever around its center of rotation 9, and now current flows from the heavy current line by way of the fuse 5, reducing-resistance 6, contact 7, 8, branching off at 11, one part going through the storage battery 12 and one part via 15 through the bell installation. By means of the first partial current the storage battery 12 is charged, and by the latter the bell installation is worked and the electromagnet 18 more strongly excited. The return line is from 12 via 13, 14; from 16 via 17, 18, 14. If the contact or push button 16 placed in the weak current circuit is released the current in the relay is interrupted, the relay armature is released, the contact 7 8 again opened and thus the heavy current line is cut out, whereby also the charging of the storage battery 12 ceases.

It would be possible to choose the size of the resistance 6 in such a manner that the current permitted to pass is just strong enough to exactly compensate the consumption of current from the battery for each time that the weak current circuit is cut in. However, the consumption is by no means always regular, particularly in the case of weak current circuits with variable load. It is therefore an essential art of the invention that charging and ischarging of the storage battery are regulated by special devices. At the same time the size of the resistance (5 which is to be included in the charging current circuit is such that the accumulators at each closing of the circuit receive more current than they give 011', in other words would necessarily become more and more strongly charged if a final limitation of this process did not take place. This can be regulated in a well known manner by any kind of charge-limiting device, a suitable arrangement being shown in Fig. 5. The connections are the same as in Fig. 1. A glow lamp can be used to advantage as leducing-reslstance 6 in the power or charg ing current circuit, as shown in the figure. In the branch circuit of the storage battery 12 a charging limiter is cut in, consisting of a suitable vessel 26 which is divided into anode compartment and cathode co'mpartment by a partition reaching up to a certain height or by a diaphragm. Both contain quicksilver as electrodes, to which the current is conducted from below by means of inserted wires. The electrodes are coated with a quicksilver salt solution, which is indicated by 27 The chemical composition of the electrolyte is of no interest here; it can be chosen according to requirements and be provided with admixtures. A suitable electroylte is a solution of mercuric chlorid in hydrochloric acid. With the cathode compartment (contemplated in the charging direction of the current) communicates a standin tube which enters the main vessel above t e level of the electrolyte and thus has always the same gas pressure as the latter. In the tube is situated a short-circuit contact 25 which is electrically connected at 24* with the return line 17. The height of the quicksilver in the tube is so chosen that the contact 25 is open when the operating storage battery is discharged to the lower admissible limit. When the charging current flows into the battery and through the cell 26 quicksilver is deposited on the cathode, while quicksilver is dissolved at the anode. The quicksilver thus increases in mass and volume in the cathode compartment; and also the quicksilver level in the tube will rise in the same measure as the metal in the cathode compartment gains in height. After a sufficient quantity of ampere-hours has flowed through the limiter as charging current of the accumulators to deposit enough quicksilver to short-circuit the contact 25*, on the next operation of the weak current circuit the current will not be conducted back through the relay electromagnet 18, but direct by way of 24, 25* to the battery; the relay therefore will not function and the charging current installation will not be cut in until, by means of the discharging current of the battery, so much quicksilver has been dissolved in what is now the anode compartment of the limiter situated to the right, and has been deposited at the left that the contact 25 has been interrupted by a corresponding fall of the quicksilver in the tube. Then the relay functions again; and by connection with the chargin current line a new charging period begins or the storage battery.

Under certain circumstances it may be advantageous to utilize the gradual increase in volume of the quicksilver situated in the cathode compartment during the charging period of the storage battery for gradually raising a float, which in its highest position brings two contacts which are placed in shunt with the relay electromagnet into connection with each other in some manner, without these contacts making electrical connection with the quicksilver of the limiter cell. The contacts, which short-circuit the electromagnet windings so that it cannot be excited, are to be completely insulated from the quicksilver. This measure is used in the connection plans of Fig. 7, 7 and 8 referred to later.

Fig. 6 shows how the change in the accumulator density of the electrolyte, which is proportional to the amount of electricity which has flowed through, can be utilized for releasing the short-circuit of the relay. It is known that the electrolyte of an accumulator becomes denser during charging, and this fact has already been utilized in order'to limit the char ing condition of the battery by means of t e gradual rise of a float constructed on the principle of the hydrometer, in which the float makes some contact or other. This well-known method is used in Fig. 6 for the purpose of the invention. In this figure 28 represents a storage cell with the plates 29 and the electrolyte 30". In a special compartment of the vessel. 31 is situated the hydrometer 3-2 which functions as a float and which on the charging of the battery rises and finally closes the short-circuit contact 33 which short-circuits the windings of the relayelectromagnet.

Particular qualities of the connection are.

shown by Figs. 2, 3, 4. Figs. 2 and 3 refer to cases in which a fixed connection of the weak current with the heavy current line is not admissible in any place when putting up the apparatus, as shown in Figs. 1 and 5 at 13 and 14 and 13", 14. This might be the case if both conductors of the heavy current line have a tension different from zero potential or earth. The condensers and the charging limiters are omitted for the sake of simplicity. Both sections of the heavy current line can then be conducted to contacts 7 7 and 7 7 which in the normal condition of the weak current circuit are open and are only connected to the weak current circuit by the attraction of the relay armature 19 19 by means of the contact springs 8", 8 8 8 If one heavy current conductor has a certain positive, and the other an equally great negative tension to zero or earth, it is advisable to place.in circuit the resistance 6 6, 6 and fuses 5 5 5 in both heavy current sections. In the figures glow lamps are chosen as resistances.

In Fig. 4 in which the charging limiter is also omitted for the sake of simplicity, the condenser 10 is not firmly connected with the positive branch of the storage battery situated in the weak current circuit, as is shown in Figs. 1 and 5, since on the disruptive discharge of the condenser the battery might become charged to an unlimited extent. One line to. the condenser branches of! at 21 or at 20 from the power current section, by preference from the latter in case the resistance 6 possesses considerable self-induction. The line connecting the condenser goes to the easily movable contact arm 22*, which on the rising of the relav lever first makes electric connection with the weak current circuit at 23. Inversely the connection of 22 and 23 continues after the opening of the contacts 7, 8. The condenser thus receives the hi h tension and makes 7, 8* free from spar s. Inthe normal position of the relay lever, after its complete return, the connection 22*, 23 is, however, broken. In accordance with the invention it is also possible to proceed in such a manner that no connection between the charging current line, at least between the parts of it which are under pressure with relation to the earth, and the weak current line, does not take place even during the charging of the storage battery. Fig. 7 illustrates this case. It is assumed in the first place that the negative charging current conductor 14 is earthed. The operating storage battery 12 serves as the working current source of the weak current circuit. A second or supplementary battery 34 is connected in series with a charging limiter 26 and the relay formed with the help of the contacts 35, 36, in such a manner that in the normal position, when the weak current circuit 15, 17 is open and the relay does not function, the positive pole of 34 is connected via contact 35, 9" and 11 with the similar pole of 12. As the negative battery poles are also connected with each other via 26, 13 (an equalizing resistance can also be connected in series with'12), both batteries are now simply connected in parallel. If the contact is closed in the weak current circuit, and the windings of 18 are not short-circuitcd by limiter 26, the electromagnet is excited, the armature 19 is attracted, the battery 34 is thereby disconnected from the weak current circuit and connected to the charging current circuit at 36, as is obvious without further explanation from the figure. Supplementary battery 3i is thereby charged, without the weak current circuit having connection with 36. If the contact in the weak current 1nstallation ceases, 19 is released, the battery 3% is disconnected from the charging current circuit and at the same time is closed through 37 on battery 12. The operating battery 12 thereby receives a part of the charge of supplementary battery 34 and remains constantly ready for working. If battery 34 is charged to its full capacity the charging limiter 26 short-circuits the electromagnet 18 (as shown in Figs. 5 and 6) until battery 34 is sufiiciently discharged to cease operatin the limiter 26.

Fig. 7 shows he case in which both power current conductors have high pressure wlth regard to earth contacts 35 and 36. resemble 35 and 36, but are connected to the negative wire. There is also the complete disconnection of the weak current circuit, even during the charging on the negat ve side. The same idea can also be carried out-see Fig. 8in such a manner that the charging limiter 26 laces a relay 18 in circuit at the lower discharge limit, the relay not being connected in series wlth the weak current line, but parallel to it and to the battery 12; if necessary with the equlllzing resistance 40 placed in circuit. If 3} is discharged to the bottom limit, 18 is placed in circuit and excitedfrom the battery 12 The relay armature actuates a bipolar switch 37, 37 in such a manner that the connection with the weak current line is broken at the contacts 39 39' and made instead at 38, 38 with the charging current line, whereby 34 is charged until the charging limiter comes into operation. Then by releasing the relay armature the storage battery 34* is again connected in paral el to 12. Any current that may be required in the weak current line is supplied by battery 12 during the disconnecting and charging process of battery 34?.

In the case of alternating current it is possible to proceed in accordance with the connections hitherto indicated in their various forms of execution. It is only necessary to place in the charging circuit a valve cell or rectifier cell in a sultable manner in the power current line immediately after the reducing-resistance (lamp), so that only impulses of the alternating current flowing through the power current line are allowed in pass in the direction in which the storage battery is charged. It is, however, better for th1s purpose first to step down the alternating current to a lower pressure. A connection suitable for this urpose, in which no-load losses of the trans ormer do not take place, is shown in Fig. 9, the charging limiter being omitted. The line 3*, 4 branches off from the heavy current line 41, 42 which conducts the alternatin current. Through the operation of there ay 18 on contact being made in the bell installation 16 the contact 43 is connected with 44", and the alternating current flows through the primary winding 45 of the transformer, which is provided with parallel condenser 10. The current of the secondary winding 46 goes partly through the weak current network via 15, 17, 18, 24, 13, 53 and back through the condenser 47 which permits alternating current to pass; the positive current impulses within the meaning of the figure, which charge the accumulator, also go without hindrance from 11" via 12*, resistance 40 and through the permeable valve cell 52 (rectifier cell) in the direction of the arrow. To actuate the weak current installation on placing a contact in circuit the current must flow through the battery 12 in the opposite direction to the arrow. As the valve cell 52, however, would not permit this, the following arrangement is made. In the normal position, when the relay armature is released, the resistance 40 and the valve cell 52 are shunted by a branch line 49, 50, as well as the contact device 48, 51, and the current can flow without hindrance to o crate the bell and relay. When the relay ever has tipped almost quite round through the attraction of the armature 19, the shunt circuit will be opened shortly before the closin of 43, 44 by 48, 51, so that the valve cel can come into operation for charging the battery. The condenser 47*, which does not permit direct current to pass, prevents in a normal position the battery 12" from becoming discharged by way of the secondary winding 46" of the transformer. It can-be replaced by an interruptor-contact which is open in the normal position and which is also governed by the relay.

Devices by means of which an auxiliary current source and relay prevent the no-load losses of transformers, are known, but the arrangement described in the present invention varies from others heretofore used, by the fact that there is here shown means in the same circuit for automatically charging the source of auxiliary current.

In so far as condensers are adapted for replacing storage cells by receiving and giving off charging energy, they can be used in the connections designated above instead of such cells.

What I claim is 1. A system of operating weak-current installations by means of storage batteries, comprising a storage battery, a relay, a charging circuit, means to connect said battery with said charging circuit when the relay is energized, and means to short-circuit said relay when the charge-content of said battery exceeds a predetermined value.

2. A system of operating weak current installations by means of storage batteries comprising a weak current circuit, a charging circuit, two storage batteries one connected constantly in the weak current circuit and normally in parallel with the second, an automatic switch in the weak current circuit adapted to control the connection of the two batteries with each other and the connection of the second battery with the charging circuit during the discharge of the first battery.

3. A system of operating weak current installations by means of storage batteries comprising a weak current circuit, a charging circuit, two storage batteries one connected constantly in the weak current circuit and normally in parallel with the sec end, an automatic switch in the weak current circuit adapted to control the connection of the two batteries with each other and the connection of the second battery with the charging circuit during the discharge of the first battery and a charge limiter connected in the circuit of the second battery.

In testimony whereof I afiix my signature in presence of two witnesses.

FRITZ SCHltflTER.

Witnesses:

JEAN Gmmn, CARL GRUND.

llt

It is hereby certified that in Letters Patent No. 1,141,836, granted June 1, 1915,

upon the application of Fritz Schrfiter, of Wilmersdorf, near Berlin, Germany,

for an improvement in Devices for Working Weak-Current Installations, errors appear in the printed specification requiring correction as follows: Page 2, lines 120121, strike out the word accumulator; same page, line 121, before the word electrolyte insert the word accumulator; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 17th day of August, A. D., 1915.

[SEAL] J. T. NEWTON,

Acting Cbmmiss'ioner of Patents. 

